Nalm-6 (A) and Reh (B) cells were treated with Bapta-AM (5 μM) and dexamethasone (Dex, 100 nM) alone or in combination for 48 h. Cell death was detected by MTT metabolic colorimetric assay. Data are representative of triplicate experiments. (C) ALL Reh cells were treated for 48 h with increasing concentrations of dexamethasone (Dex) alone or in association with Bapta-AM (5 μM). (D) ALL Reh cells were treated for 48 h with indicated concentration of Bapta-AM alone or in association with dexamethasone (Dex, 100 nM). The values of control cells were considered as 100%. Data represent the means ±S.E.M. (n=3). *P<0.05 vs Dex or Bapta-AM alone treatment. Cell cycle distribution (E, F) and apoptosis (G, H) were determined respectively by PI staining and Annexin V/FITC-PI staining followed by FACS analysis. *P<0.05 vs dexamethasone alone treatment (E, F). (H) The percentage of apoptotic cells was calculated by the percentage of annexin V-FITC positive and annexin V-FITC/PI-positive population. Combination index (CI) value < 1 (0.58 in Nalm-6 and 0.45 in Reh cells) indicates that the drugs are significantly synergistic. Data represent the mean ± S.E.M. (n=3).